1. Field of the Invention
This invention relates to a composite of a metallic material and vulcanized rubber.
More particularly, this invention relates to a composite such as a tire, a belt and a hose which comprises an improved adhesion between the metallic material and vulcanized rubber.
2. Description of the Prior Art
Heretofore, upon preparing a composite composed of the metallic material and vulcanized rubber, the surface of the metallic material was coated with brass in order to obtain an improved adhesion strength between the metallic material and vulcanized rubber.
However, when the high adhesion strength is desired in said brass coating process it was necessary to prevent the deterioration of the surface of the metallic material due to the moisture attached thereto during the production stages, and also to avoid that the moisture enters the rubber, or to prevent the rubber from absorbing the moisture.
Further, when placed under a highly humid atmospheric condition, it was extremely difficult that the metallic material and the rubber are kept free from the moisture.
Accordingly, this tends to occur the defaults such that the adhesion strength between the metallic material and vulcanized rubber is lowered remarkably, and that the rubber peels off the metallic material. When a composite was a tire, the earlier damage of the tire was often resulted.
As set forth in Japanese Patent Application No. 44648/1971, the present inventors have carried out the method of coating additionally a thin film of the metals in Group IV of the Periodic Table on the surface of the metallic material which was previously coated with brass so that consistently high adhesion between the metallic material and rubber may be preserved without an adverse effect due to the moisture.
However, according to the above method, it was necessary to carry out twice the thin film coating of said metals.